Device for simultaneously controlling rotary shafts of a plurality of variable resistors

ABSTRACT

A control device is provided which is capable of simultaneously controlling the rotary shafts of a plurality of variable resistors by one control shaft. The device is, for example, used in a stereophonic electric gramophone in which a plurality of volume controls must be simultaneously adjusted. A plurality of variable resistors are mounted coaxially on a pair of opposed walls of an outer frame which in turn is fixed in a casing, and an inner frame is rotatably carried in the outer frame by the rotary shafts of the variable resistors mounted on the outer frame. Another plurality of variable resistors are mounted on a pair of opposing walls of the inner frame at right angles to the walls of the outer frame mounting the one plurality of variable resistors, in such a manner that the axes of the other plurality of variable resistors are at right angles to those of the one plurality of variable resistors. One control shaft extending through the top of the casing is fixed to the rotary shafts of these variable resistors, whereby the variable resistors mounted on the outer and inner frame may be simultaneously or selectively adjusted by inclining the control shaft.

' United States Patent I 1 1 3,7l1,81 1 Oka et al. 1 Jan. 16, 1973 DEVICE FOR SIMULTANEOUSLY Primary Examiner--Lewis H. Myers CONTROLLING ROTARY SHAFTS OF A PLURALITY OF VARIABLE RESISTORS [75] Inventors: Shunzo .Oka; Hlsao Kitahara, both of Hirakata, Japan [73] Assignee: Matsushita Electric Industrial Co.,

Ltd., Osaka-fu, Japan [22] Filed: Dec. 15, 1971 21 Appl. No.1 208,091

[30] Foreign Application Priority Data Dec 17, 1970 Japan ..45/l I384) Dec. 17, 1970 Japan ..45/l27383 Dec. 17, i970 Japan r ..45/l27384 Dec. I7. 1970 Japan ..45/l27385 [52] US. Cl ..338/l28 [51] Int. Cl. ..H0lc 9/02 [58] Field of Search ..338/128, 130,131, 320

[56] References Cited UNITED STATES PATENTS 3.365975 l/l968 Hathaway ..338/l28 X 3,372,359 3/l968 Wilson ..338/l28 Assistant Examiner-D. A. Tone Attorney-Milton .1. Wayne 01 ill.

| 57 ABSTRACT A Control device is provided which is capable of simultaneously controlling the rotary shafts of a plurality of variable resistors by one control shaft. The device is, for example, used in a stereophonic electric gramophone in which a plurality of volume controls must be simultaneously adjusted. A plurality of variable resistors are mounted coaxially on a pair of opposed walls of an outer frame which in turn is fixed in a casing, and an inner frame is rotatably carried in the outer frame by the rotary shafts of the variable resistors mounted on the outer frame. Another plurality of variable resistors are mounted on a pair of opposing walls of the inner frame at right angles to the walls of the outer frame mounting the one plurality of variable resistors, in such a manner that the axes of the other plurality of variable resistors are at right angles to those of the one plurality of variable resistors. One control shaft extending through the top of the casing is fixed to the rotary shafts of these variable resistors, whereby the variable resistors mounted on the outer and inner frame may be simultaneously or selectively adjusted by inclining the control shaft.

4 Claims, 6 Drawing Figures at a! PATENTEDJAN 16 I975 SHEET 2 BF 3 FIG. 3

FIG. 4

l 7 N Y 6 0 d 2 5 d A M b M 8 B 2 2 r 52 II b 4 la 119ml 6 0 O 3% W O\ I 7 C 2 2 l |M 9 5.0 A I l 5 7 BACKGROUND OF THE INVENTION The present invention relates to generally a ganged variable resistor, and more particularly to a device for simultaneously controlling with only one control shaft the rotary shafts of a plurality of variable resistors.

For example, in a stereophonic electric gramophone, a plurality of volume controls or variable resistors are ingeneral disposed for respective channels, and are adjusted independently by individual knobs. Therefore, the harmonious volume control is a difficult and cumbersome operation. Furthermore, the number of component parts is increased, whereby the circuit becomes complex and uneconomic.

One of the objects of the present invention is therefore to provide a device for simultaneously controlling, with only one control shaft, the rotary shafts of a plurality of variable resistors.

Another object of the present invention is to provide a control device for simultaneously controlling a plurality of variable resistors which is simple in operation.

Another object of the present invention is to provide a device for simultaneously controlling a plurality of variable resistors which can be economically manufactured at less cost than conventional devices of this type.

SUMMARY OF THE INVENTION According to the present invention, a plurality of variable resistors are mounted on an outer frame and an inner frame disposed in the outer frame in such a manner that the axes of the rotary shafts of the variable resistors coaxially mounted on the outer frame may be at right angles to those of the rotary shafts of the variable resistors mounted on the inner frame. The inner frame is carried by the rotary shafts of the variable resistors mounted on the outer frame. A control shaft is fixed to the rotary shafts of the variable resistors mounted on the inner frame so that the variable resistors mounted on both the outer and inner frames may be simultaneously controlled by the control shaft. According to the present invention, one control shaft can simultaneously control a plurality of variable resistors in a manner described above so that the ganged variable resistor in accordance with the present invention is best suited for use in, for example, a four-channel stereophonic electric gramophone for volume and balance controls. According to one aspect of the present invention, the variable resistors mounted on the outer frame can be adjusted independently of those mounted on the inner frame, and vice versa, so that the balance and volume controls can be positively effected in a very simple manner.

The device in accordance with the present invention has a simple construction such that a plurality of variable resistors are mounted on both the outer and inner frames, the latter being carried by the rotary shafts of the variable resistors mounted on the outer frame, and the control shaft is fixed directly or indirectly to the rotary shafts of the variable resistors mounted on the inner frame. Therefore, the device can be manufac tured which is compact in size and at less cost.

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the preferred embodiment thereof taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a top view of one preferred embodiment of the present invention;

FIG. 2 is a side view thereof;

FIG. 3 is a sectional view taken along the line A-A of FIG. 2;

FIG. 4 is a sectional view taken along the line B-B of FIG. 1;

FIG. 5 is a sectional view taken along the line CC of FIG. I; and

FIG. 6 is a sectional view thereof used for explanationof the mode of operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT The bottom of a box-shaped casing l is open, and an aperture 2 is formed in the top of the casing. A flexible dust-proof member 4 made of, for example, rubber is fixed to the undersurface of the top of easing 1 along the peiiphery of the aperture 2. The top is further provided with a plurality of holes 3 (four holes in the instant embodiment at the corners) for mounting a ganged variable resistor on a chassis.

Within the casing 1 is disposed a box-shaped outer frame 6 having four L-shaped projections Sa-Sd which are joined to the casing l with setscrews 7. Two variable resistors'l0 and 11 are mounted on the opposing faces 6a and 6b of the outer frame 6 with nuts 12 and 13, respectively, in such a manner that their rotary shafts 8 and 9 extend inwardly into the outer frame 6 in line with each other. The leading ends of the rotary shafts 8 and 9 of the variable resistors 10 and 11 are securely fixed with washer-like rings 15 and 16 to the opposing walls 14a and 14b of an inner frame in the form of a box, respectively, which is disposed within the outer frame 6. Therefore, it is seen that the inner frame 14 is caused to rotate together with the rotary shafts 8 and 9 of the variable resistors 10 and 11.

Similarly, rotary shafts l7 and 18 of variable resistors 19 and 20 are extended inwardly through the opposing walls 14c and 14d of the inner frame 14, and are securely fixed thereto with nuts 21 and 22, respectively. The rotary shafts l7 and 18 are coaxially aligned relative to each other, and the axes of these rotary shafts l7 and 18 are at right angles to those of the rotary shafts 8 and 9 of the variable resistors 10 and 11.

Therefore, it is seen that the rotary shafts l7 and 18 are caused to rotate when the inner frame 14 is rotated. The rotation of the inner frame 14 is limited since leg members 25a and 25b of the inner frame 14 engage with projections 23a and 23b; and further engage with projections 24a and 24b extending from the walls 6a and 6b of the outer frame 6. I

The leading ends of the rotary shafts l7 and 18 of the variable resistors 19 and 20 are fitted into the holes formed in the opposing ends of a coupling member 26 and are securely fixed thereto. As a result, the rotary shafts l7 and 18 are rotated in unison with the coupling member 26. A control shaft 27 is extended through a center hole of the coupling member 26, and is securely fixed thereto with a flange 28 integrally formed with I described. When the control shaft 27, which is positioned at the center as shown in FIG. 4, is displaced in the direction of the double-pointed arrow 11, forceis exerted through the coupling member 26 to the rotary shafts 17 and 18 of the variable resistors 19 and 20, and

then to the inner frame 14. Since the inner frame 14 is disposed for rotation about the axes of the rotary shafts 8 and'9 of the variable resistors and 11, it is rotated.

in unison with the shafts 8 and 9 as shown in FIG. 6, whereby the resistance values of the variable resistors 10 and 11 are simultaneously varied.

In this case, the force applied to the control shaft 27 is applied to the rotary shafts 17 and 18 of the variable resistors 1.9 and 'at right angles to their axes of rotation so that the rotary shafts 17' and 18 are not rotated. Asa result, the resistance values of the variable resistors 19 and 20 remain unchanged, whereas only the resistance values of the variable resistors 10 and 11 are varied.

As described above, the range of the displacement of the control shaft 27 is limited by the movement of legs a and 25b of the inner frame 14 which engage with the projections 23a, 23b, 24a and 24b of the outer frame 6, whereby the variable resistors 10 and 11 are prevented from being damaged. i

Next when the control shaft 27 is displaced in the direction indicated by the double-pointed arrow b as shown in FIG. 5, the force is transmitted through the coupling member 26 to the rotary shafts 17 and 18 of the variable resistors 19 and 20 to rotate them, whereby the resistance values of the variable resistors 19 and 20 are varied. In this case, the force is applied to the rotary shafts 8 and 9 of the variable resistors 10 and 11 at right angles to their axes of rotation so that they are not rotated. As a result, the resistance values of the variable resistors 10 and 11 remain unchanged. The displacement of the control shaft 27 is also limited since the projection 31 of the semispherical cover engages with the upper ends of the walls 14a and 14b of the inner frame 14, whereby the variable resistors 19 and 20 can be prevented from being damaged. It is seen that the range of the displacement of the control shaft 27 is determined depending upon the upper positions of the walls 14a and 14b of the inner frame 14. and the diameter of the projection 31.

When the control shaft 27 is displaced in the direction indicated by the arrow b from the position shown in FIG. 6 in which the rotary shafts 8 and 9 of the variable resistors 10 and 11 are shown as being rotated in unison with the inner frame 14, the direction b is at right angles to the axes of rotation of the rotary shafts 8 and 9 of the variable resistors 10 and 11. Ac-

cordingly the rotary shafts I7 and 18 of the variable resistors l9 and 20 are rotated while the variable resistors 8 and 9 remain in the positions shown in FIG. 6, whereby the resistance values of the variable resistors 19 and 20 are varied. In this case, even when the rotary shafts 8 and 9 are at any position between the extremities of their angle of rotation, the control shaft 27 which is displaced in the direction indicated by the arrow b will not cause the rotations of the rotary shafts 8 and 9. As a result, the adjusted resistance values of the variable resistors 10 and 11 remain unchanged.

After the desired resistance values of the variable resistors 19 and 20 have been attain-ed by shifting the control shaft 27 in the direction indicated by the arrow b, the control shaft 27 may be displaced in the direction indicated by the arrow a to rotate only the rotary shafts of the variable resistors 10 and 11 without causing the rotation of the rotary shafts 17 and 18 of the variable resistors 19-and 20. As a result, only the resistance values of the variable resistors 10 and 11 are varied, whereas those of the variable resistors 19 and 20 remain unchanged.

Even when the control shaft 27 is shifted in the direction indicated by the arrow a when the rotary shafts 17 and '18 are at the extremities of their angle of rotation at, which the projection 31 engages with the upper ends of the walls 14a and 14b of the inner frame 14, the rotary shafts l7 and 18 are not affected by the rotary forces from the control shaft 27 so that the resistance values of the variable resistors 19 and 20 remain unchanged. Thus, the resistance values of the two pairs of variable resistors 10 and 11; and 19 and 20 can be varied independently by displacing the control shaft 27 in the direction indicated by the arrow a or b. I

When the control shaft 27 is displaced in a direction at 45 to the direction indicated by the arrow a, that is, also at 45 to the direction indicated by the arrow b, the force or motion of the control shaft 27 is resolved into the two directions a and b. As a result, the forces are applied to both pairs of the rotary shafts 8 and 9; and the rotary shafts l7 and 18 of the variable resistors 10 and 11; and the resistors 19 and 20. Thus, their resistance values are simultaneously adjusted.

The semispherical cover 30 is rotated in unison with the displacement of the control shaft 27v in the directions indicated by the arrow a or b or in any other direction, but the diameter of thesemispherical cover 30 is so selected that its peripheral edge will not be exposed out of the aperture 2 in the top of the casing 1. Therefore, the ganged variable resistor in accordance with the present invention has a pleasing external appearance. Furthermore, the dust-proof member 4 is disposed so that dust or the like can be positively prevented from into the inside of the casing 1.

In the instant embodiment, the two pairs of variable resistors have been described as being mounted upon the outer and inner frames in opposed relation, respectively, but it is understood that duplex or triplex variable resistors may be also mounted in a similar manner as described above. For example, a duplex variable resistor is mounted on one wall of the outer frame, whereas another duplex variable resistor is mounted on a wall of the inner frame at right angles to the wall of the outer frame upon which is mounted the one duplex variable resistor, in such a manner that their axes cross at right angles at the center of the coupling member.

Short shafts are fitted into the opposing walls of the outer and inner frames, respectively, so as to rotatably support the inner frame and the coupling member.

The ganged variable resistor has been described as being used, for example, in a stereophonic electric gramophone, but it is understood that it may be used in any other device which requires a plurality of variable resistors which must be adjusted simultaneously.

What is claimed is:

1. A device for simultaneously controlling the rotary shafts of a plurality of variable resistors comprising a. acasing,

b. an outer frame securely fixed to said casing in said casing,

c. a first group of a plurality of variable resistors coaxially mounted upon a pair of opposing walls of said outer frame, the rotary shafts of said first group of a plurality of variable resistors being extended inwardly into said outer frame,

d. an inner frame whose one pair of opposing walls are supported by said rotary shafts of said firstgroup variable resistors for rotation in unison therewith in said outer frame,

e. a second group of a plurality of variable resistors whose rotary shafts are coaxially supported by the other opposing walls of said inner frame and at right angles to said rotary shafts of said first group variable resistors, said rotary shafts of said second group variable resistors being extended inwardly into said inner frame, and

f. a control shaft which is extended through the top of said casing and whose lower end is connected to said rotary shafts of said second group variable resistors, whereby said rotary shafts of said firstgroup variable resistors and said rotary shafts of said second-group variable resistors are rotated when said control shaft is inclined.

2. A device as set forth in claim 1 wherein the range of inclination of said control shaft is limited by the engagement of stop members extending from said inner frame with projections extended from said outer frame and by the engagement of said control shaft with said inner frame.

3. A device as set forth in claim 1 wherein a cover member having a semispherical surface is fitted over said control shaft in such a manner that an aperture formed in said top of said casing may be closed by said cover member within the range of inclination of said control shaft.

4. A device as set forth in claim 3 wherein a dust-proof ring fixed to the undersurface of said top of said casing around said aperture is brought into resilient contact with the semispherical surface of said cover member. 

1. A device for simultaneously controlling the rotary shafts of a plurality of variable resistors comprising a. a casing, b. an outer frame securely fixed to said casing in said casing, c. a first group of a plurality of variable resistors coaxially mounted upon a pair of opposing walls of said outer frame, the rOtary shafts of said first group of a plurality of variable resistors being extended inwardly into said outer frame, d. an inner frame whose one pair of opposing walls are supported by said rotary shafts of said first-group variable resistors for rotation in unison therewith in said outer frame, e. a second group of a plurality of variable resistors whose rotary shafts are coaxially supported by the other opposing walls of said inner frame and at right angles to said rotary shafts of said first group variable resistors, said rotary shafts of said second group variable resistors being extended inwardly into said inner frame, and f. a control shaft which is extended through the top of said casing and whose lower end is connected to said rotary shafts of said second group variable resistors, whereby said rotary shafts of said first-group variable resistors and said rotary shafts of said second-group variable resistors are rotated when said control shaft is inclined.
 2. A device as set forth in claim 1 wherein the range of inclination of said control shaft is limited by the engagement of stop members extending from said inner frame with projections extended from said outer frame and by the engagement of said control shaft with said inner frame.
 3. A device as set forth in claim 1 wherein a cover member having a semispherical surface is fitted over said control shaft in such a manner that an aperture formed in said top of said casing may be closed by said cover member within the range of inclination of said control shaft.
 4. A device as set forth in claim 3 wherein a dust-proof ring fixed to the undersurface of said top of said casing around said aperture is brought into resilient contact with the semispherical surface of said cover member. 